arcpy tips & tricks - recent proceedings · 2017-08-11 · -debugging small units of...

ArcPy Tips & Tricks

Clinton Dow – Geoprocessing Product Engineer @ Esri

Tip #1 – ArcPy in an IDEGIS from the comfort of your development environment

• Recommended IDEs- PyCharm

- Python Tools for Visual

Studio

- Spyder

- Eclipse with PyDev

- Wingware

Tip #1 – ArcPy in an IDEGIS from the comfort of your development environment

• Integrated Development Environments

- Debuggers

- Test Frameworks

- Coverage

- PyLint/pycodestyle

- Version Control Integration

- Refactoring Tools

- Virtual Environment Support

- AutoComplete

Tip # 2 – Decouple Your Tool LogicToolboxes, Python Toolboxes, Interpreters, Command Line, Services…

• Multiple ways to create tools- ArcGIS Toolbox (.tbx)

- Python Toolbox (.pyt)

- Stand-alone Scripts (.py)

- Interactive Python Window

• Test Driven Development

• Distutils to create packaged codeSharing

Install into tools as needed

Decoupled ArcPy Tool Logic DiagramModularized Code

Tip #3 – There Must Be A Better Way!Never Underestimate The Python Standard Library!

• Raymond Hettinger- Transforming Code Into Beautiful, Idiomatic Python

- https://www.youtube.com/watch?v=OSGv2VnC0go

- Beyond PEP 8 – Best Practices for Beautiful, Intelligible Code

- https://www.youtube.com/watch?v=wf-BqAjZb8M

Tip #4 – Comprehensions with CursorsUsing Pure Python Data Types to Work with Feature Classes

import arcpy

data_path = r"C:\Path\to\feature\class"

def cursor_list_comprehension(path):

l = [row for row in arcpy.da.SearchCursor(path, ["SHAPE@", "Language"])]

return l

def cursor_dictionary_comprehension(path):

d = {row[0]: row[1:] for row in arcpy.da.SearchCursor(path, ["OID@", "MsgText", "Language"])}

return d

def cursor_generator_comprehension(path):

g = (row for row in arcpy.da.SearchCursor(path, ["SHAPE@", "Language"]))

return g

def cursor_generator_statement(path):

with arcpy.da.SearchCursor(path, ["OID@", "MsgText"]) as cursor:

for row in cursor:

yield str(row[0])

Tip #5 – Filter & Map with ComprehensionsUsing Pure Python Data Types to Work with Feature Classes

import arcpy

data_path = r"C:\Path\to\feature\class"

def cursor_comprehension_map(path):

# Map function

# m = map(lambda x: x[0] + 1.0, [row for row in arcpy.da.SearchCursor(path, ['OID@'])])

m = [row[0] + 1 for row in arcpy.da.SearchCursor(path, ['OID@'])]

return m

def cursor_comprehension_filter(path):

# Filter function

# f = filter(lambda x: x ==1, [row for row in arcpy.da.SearchCursor(path, ['OID@'])])

f = [row for row in arcpy.da.SearchCursor(path, ['OID@']) if row[0] == 1]

return f

Tip #6 – Collections ExampleUsing Pure Python Data Types to Work with Feature Classes

from collections import Counter

import arcpy

data_path = r"C:\Users\clin8331\Desktop\Temp\tw.gdb\tw_lang_europe"

def count_field_occurances(data_path):

c = Counter()

with arcpy.da.SearchCursor(data_path, ["OID@", "Language"]) as cursor:

for row in cursor:

c[row[1]] += 1

return c

Tip #7 – Use Third Party Packages

• Anaconda- Curated collection of popular Python packages

- Handles dependencies

- Integrated into ArcGIS Pro

• Pip- Python Package Index (PyPI)

- Over 100k Packages

- Works with 10.x and Pro

Tip #8 – Pathlib makes paths easy!

• Object-Oriented Paths- Native Python in 3.4+

- Install via Pip in 2.7.x

• Folder hierarchy as list

- Access parent folder as index 0

- Parent of parent is index 1, etc.

• File Comparison

- Compare contents of files easily

Tip #9 - Help us make ArcPy better!

• GeoNet- http://geonet.esri.com

- https://geonet.esri.com/community/developers/gis-developers/python

• Conda Support Email- conda@esri.com

• ArcPy Café- https://arcpy.wordpress.com/

Conclusion• IDEs are useful tools for aiding development

• The Python Standard Library is very powerful on its own

• Modularized code is your friend

- Easier to follow

- Reuse code

- Debugging small units of functionality

• Interact with us!

- cdow@esri.com

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Clinton Dow – cdow@esri.com